The recent spate of slaughters in European cities is having a “decreasing impact” on holiday cancellations and tourist numbers, a leading travel boss has said.

Tom Jenkins, chief executive of the European Tour Operators Association (ETOA), said the public has an increasingly “sophisticated” understanding of “gruesomely familiar” terror attacks and “realise it can happen anywhere”.

Barcelona will remain an attractive destination, with “minimal cancellations and a modest reduction in demand for a relatively short time”, he said.

The tourism chief said: “These things are designed to have an impact. We’re finding the impact is gradually decreasing. The public are becoming more sophisticated ... they realise Europe is not one homogeneous destination.

“People realise this can happen anywhere. Because it happens in one location doesn’t make it more likely to happen there again.

“The fear generated by such events is irrational, but people are starting to rationalise it better. Thirty years ago, you would have a major haemorrhaging in demand.”

Around half of holiday reservations from North America to Europe in 1986 were cancelled following America’s bombing of Libya, with travellers fearing reprisal attacks, he added.

Meanwhile, resorts in Tunisia have been deeply affected by the murderous rampage of Seifeddine Rezgui, who armed with an assault rifle shot dead holidaymakers on the beach and at hotels in Sousse in June 2015.

The 38 victims, included 30 Britons and two Scots couples.

Mr Jenkins said Chinese and Japanese visitors were more likely to be deterred from visiting Europe by attacks than other nationalities.

The Association of British Travel Agents said tourists should “remain alert and vigilant” in areas with lots of people and travellers should check their flight status.

Foreign and Commonwealth Office advice is for anyone in the immediate area of the attacks to follow the advice of police and officials.

Meanwhile, a British Airways spokesman said: “Customers due to travel to or from Barcelona in the coming days are being offered a range of options if they wish to bring forward or postpone their journey, and we encourage anyone with concerns about their booking to contact us or their travel agent.”

Thomson cancelled excursions to Barcelona yesterday.